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    <script>
        // 编写函数has(arr , 60) 判断数组中是否存在60这个元素，返回布尔类型
        function has(arr, findIndex) {
            for (var i = 0; i < arr.length; i++) {
                if (arr[i] == findIndex) {
                    return true;
                }
                return false;
            }
        }
        console.log(has([1, 2, 3], 'a'));
    </script>
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